I'm just samefagging by the way to try and regain some thumbs. I'm also waiting a period as I play Runescape (best game evar!!1!) between my comments to make it look like I'm actually different people.

Football was initially called soccer. Also, the prefix "foot" originated not because of the amount of interaction between feet and the ball, but because it differentiated the sports from those played on horses. (Many early forms of football involved carrying balls, but used "foot" because they were played on foot.

Also, American football is referred to as football because it derived from rugby football in the first place. Initially american football used to be a lot like rugby, but the game changed and the name did not.